Why am I getting a '500 internal server' when deploying content?

Why am I getting a '500 internal server' when deploying content?

This error message will appear when you try and deploy a sequence, which is assigned to a device, which has no signs in it. 
Update your sequence and you should have no problems in deploying content. 
With a newer release we are hoping that the error message will contain more useful information regarding the content of your sequences.